1. Technical Field
The present invention relates to a probe which is a sensor immersed in a molten metal to measure temperature of the molten metal, and more particularly, to a holder on which a probe is mounted.
2. Description of the Related Art
A holder on which a probe is mounted refers to a device for connecting a measuring unit to a long axis body having one end into which a probe can be inserted and mounted through a connector which can be electrically and mechanically connected to the probe and a wire extending to the other end of the connector.
Holders generally include a manual holder designed to be directly immersed in a molten metal by an operator holding a grip extending from a body thereof, and an automatic holder mounted on a separate immersion unit to be immersed into a molten metal.
One example of the automatic holder is disclosed in Korean Patent No. 10-0471626 (published on Mar. 8, 2005) entitled “Probe and Connector for Connection of Holder”. One example of a manual holder is disclosed in U.S. Pat. No. 4,893,516 (published on Jan. 16, 1990) entitled “METAL CONTACT MEMBER FOR A MEASURING LANCE FOR TAKING MEASUREMENTS IN METAL MELTS”.
If a holder is used for a long period of time, a connector may be contaminated by tar generated in a probe. In this case, the holder cannot be used further and must be replaced.
In order to solve this problem, in the automatic holder, a gas is blown from a lance, on which a holder is mounted, to prevent contamination of a connector. However, this configuration also has limitations, and gas purging is also limited according to measurement conditions.
Further, efforts have been made to solve this problem using a method of replacing only a tip connector of a holder instead of replacing the entirety of the holder, but it is necessary to separately connect a compensation lead wire which is an extension line in the holder and the replacing operation is very inconvenient.
Moreover, due to characteristics of the probe in which even a metal case of the holder is used as an electric connection unit according to a measurement target, part of a connector which will be replaced must be firmly mechanically and electrically coupled. However, high external pressure, vibration, and rapid change of temperature applied to the probe immersed in the molten metal provide a loose coupling state, thereby causing erroneous measurement due to unstable contact.
One example of a holder employing a conventional replacement type is disclosed in Korean Unexamined Utility Model Publication No. 20-2000-0001626 entitled “Molten Steel Temperature Measuring Apparatus”.
Although a fixing pin method disclosed in this document has been used as the best method for preventing failure due to vibration, it is difficult to treat the fixing pin due to its small size upon replacement of the fixing pin and a separate tool is needed to attach and detach the fixing pin.
According to this document, although a terminal rod is configured to resiliently support an embedded terminal rod and a terminal ring, there is a very high possibility of contact instability due to vibration during measurement and it is difficult to commercialize the product due to its complex structure.